Steyr Arms has filed a lawsuit against Sig Sauer claiming that Sig has infringed on Steyr's patent with the P320 and P250 removable chassis system.
The complaint, filed by Steyr May 3rd in U.S. district court for the norther district of Alabama references patent US6260301 which was filed by Steyr in 1999 and approved in 2001. The patent is for a handgun with a removable chassis, and quoting from the patent;A pistol comprising a housing; a barrel slide movably mounted on the housing for movement in a firing direction with respect to a barrel; and a trigger mechanism located, at least in part, within the housing, the improvement which comprises a multifunction metal part removably insertable within said housing, said multifunction metal part being provided with guides for the barrel slide and means for supporting the trigger mechanism, said multifunction metal part and housing are each provided with a transverse hole which receives a shaft for connecting the housing and the multifunction metal part together, the housing has a rear wall which is provided with a recess for receiving a projection on the multifunction metal part the multifunction metal part includes control means for locking said barrel in the barrel slide.This does appear to be remarkably close to the P320 and P250 pistols that uses a removable chassis system to make the pistols modular.
Sig Sauer has recently won the contract for the U.S. Army's competition of a new service pistol. Steyr is demanding that a preliminary and permanent injunction is placed against Sig selling any more of these firearms. It is as of yet unclear what, if any, impact this injunction may have against Sig's contract with the U.S. Army, and if any or how much of the contract may be paid to Steyr in licensing.
Steyr's patent US6260301: https://www.google.com/patents/US6260301